Stools are widely utilized for a number of purposes, but specifically, are utilized by physicians and medical and dental personnel when performing operations and other procedures upon a patient who is lying on a table or seated in a chair. The patients and parts of their bodies may be located at various different heights and positions with respect to the seated physician, and therefore, it is generally necessary to raise and lower the height of the stool seat during the course of the operation so that the physician may perform the operation on the different patient parts and areas without leaving the seated position or unnecessarily stretching or bending. To this end, a number of currently available stools are infinitely height adjustable and generally include a seat mounted on a post which contains a lifting mechanism to allow the level of the seat to be raised and lowered upon actuation of the lifting mechanism. The seat is usually mounted to be rotated by the physician in a complete circle around the post for convenience. With such stools, it is necessary to provide some kind of actuation level for the lift mechanism of the stool located externally of the seat and post to allow the physician to actuate the lifting mechanism and raise and lower the seat level.
Some versions of height adjustable stools provide hand accessible actuation devices including levers and handles which are located proximate the seat and are grasped by the physician's hand and manipulated in a predetermined direction to change the seat height. However, such actuation devices are inconvenient and difficult for the physician to use because they require the physician to stop the operation, put down any medical implements he is using and manipulate the device with his hand. This might not be possible during a particularly critical point of the operation, and the physician may be forced to stand or do the operation at too low of a level.
Therefore, other examples of height adjustable stools utilize foot actuating devices which may be moved with a foot to actuate the lift mechanism and raise and lower the seat level, therefore leaving the hands of the physician free. Some of these stools include pedals or button-like devices which may only be actuated one particular position around the base of the stool. These versions require the physician to pivot the stool seat or stool base around the post in order to press down upon or otherwise actuate the pedal or bottom. While freeing the physician's hands, these stools present other difficulties because the actuation device may be located behind the physician or too far to the side during the critical time of the operation, requiring him to interrupt the operation and turn the stool or to continue the operation standing up or in an abnormal seated position. As a result, constantly rotating the stool around interrupts the medical operation much the same way that hand-actuation of the device does.
Still other stool versions are foot actuated and eliminate the necessity of constantly rotating the seat around the stool to find the actuation device by utilizing a circular pedal or annular flange which extends around the post of the stool and is accessible from any position around the stool. However, the circular actuation devices or pedals utilized by such stools are all mounted at a substantial distance above the floor surface on which the stool sits. Therefore, the point of actuation, that is the point of foot contact where the foot-actuation device intersects with the seat lifting mechanism in order to raise and lower the seat, is also located substantially above the floor surface. With these stools, it is necessary for the doctor to substantialiv lift at least one leg and to shift his weight forward and away from the seat in order to access the device. This leaves the physician precariously balanced on the stool during actuation which is understandably not a desirable position for the physician during a medical operation. Further, lifting of the legs shifts the center of gravity of the physician upward on the chair and forward causing the stool to want to tip over. Still further, part of the force applied to actuate a device positioned relatively high above the floor is directed perpendicular to the post of the stool and has a tendency to push the stool base out from beneath the physician while simultaneously tipping the stool seat forward. This tendency to tip is multiplied by the force moment arm created by the elongated stool post.
Any unnecessary movement by the physician during the surgical operation, such as to locate a single actuation position from around the base of the stool or to lift his leg and shift his weight forward, backward or to either side, restricts, and undesirablv limits, the doctor in accomplishing the task at hand, i.e., operating upon the patient.
A further drawback to current versions of adjustable stools is their complicated design and large number of assembly parts which unduly increases the amount of time necessary to assemble the stool, and increases the difficulty associated with such a task, as well as the cost of the stool. Stools, such as medical stools to be used for the above-described purposes, are often assembled in the field by sales personnel or other distribution personnel, and may also be assembled by the end user of the stool, such as the physicians or other medical persons. Therefore, it is desirable to have a stool with few parts and an uncomplicated assembly so that the stool may be assembled easily, quickly, and with a very small number of necessary tools.
It is an objective of the present invention to present a stool which utilizes a foot actuation device which does not reauire an operator to substantially shift his weight or substantially lift his legs in an attempt to position his foot upon the actuation device. It is a further objective to be able to actuate the lifting mechanism without a force that will tend to push the stool out from beneath the operator or to tip the stool forward. It is still a further objective of the present invention to provide a height-adjustable stool which may be easily actuated from any position around the base of the stool by an operator's foot. It is another objective to provide an inexpensive stool which is light-weight and which uses a small number of separate parts, and which may be easily and quickly assembled in the field with a small number of tools.